I have a tow bar on my VTi-R teg and have only towed a full box trailer full of dirt before with no problems.
I would be very carefull towing a boat though since when you launch it you will have all the weight transferred to the rear and will lift weight off the front wheels and cause you to wheel spin very easily on a wet slippery ramp.
I think you woulbd be fine with a box trailer, but launching a boat, I'd pass on that